Moved null_df into its own file.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%404068

dlib/svm/null_df.h

+// Copyright (C) 2010  Davis E. King (davis@dlib.net)
+// License: Boost Software License   See LICENSE.txt for the full license.
+#ifndef DLIB_NULL_DECISION_FUnCTION_H__
+#define DLIB_NULL_DECISION_FUnCTION_H__
+
+#include <iostream>
+
+namespace dlib
+{
+
+// ----------------------------------------------------------------------------------------
+
+    struct null_df
+    {
+        /*!
+            WHAT THIS OBJECT REPRESENTS
+                This is a type used to represent an unused field in the list of template 
+                arguments of the one_vs_one_decision_function and one_vs_all_decision_function 
+                templates.  As such, null_df doesn't actually do anything.
+        !*/
+        template <typename T>
+        double operator() ( const T&) const { return 0; }
+    };
+
+    inline void serialize(const null_df&, std::ostream&) {}
+    inline void deserialize(null_df&, std::istream&) {}
+
+// ----------------------------------------------------------------------------------------
+
+}
+
+#endif // DLIB_NULL_DECISION_FUnCTION_ABSTRACT_H__
+

dlib/svm/one_vs_one_decision_function.h

@@ -13,21 +13,11 @@
 #include <map>
 #include "../any.h"
 #include "../unordered_pair.h"
+#include "null_df.h"
 
 namespace dlib
 {
 
-// ----------------------------------------------------------------------------------------
-
-    struct null_df
-    {
-        template <typename T>
-        double operator() ( const T&) const { return 0; }
-    };
-
-    inline void serialize(const null_df&, std::ostream&) {}
-    inline void deserialize(null_df&, std::istream&) {}
-
 // ----------------------------------------------------------------------------------------
 
     template <

dlib/svm/one_vs_one_decision_function_abstract.h

@@ -9,24 +9,11 @@
 #include "../any/any_decision_function_abstract.h"
 #include "../unordered_pair.h"
 #include "one_vs_one_trainer_abstract.h"
+#include "null_df.h"
 
 namespace dlib
 {
 
-// ----------------------------------------------------------------------------------------
-
-    struct null_df
-    {
-        /*!
-            WHAT THIS OBJECT REPRESENTS
-                This is a type used to represent an unused field in the 
-                list of template arguments of the one_vs_one_decision_function
-                defined below.  As such, this object doesn't actually do anything.
-        !*/
-        template <typename T>
-        double operator() ( const T&) const { return 0; }
-    };
-
 // ----------------------------------------------------------------------------------------
 
     template <